The present invention comprises an improvement over the switching apparatus disclosed in U.S. Pat. No. 4,946,022 ("the '022 Patent") granted to Davis, et al. on Aug. 7, 1990, and assigned to Stewart Systems, Inc., the predecessor-in-interest of the assignee of the present invention, the disclosure of which is incorporated herein by reference. The '022 Patent discloses a switching apparatus incorporating a double acting cylinder which is utilized to locate a switching channel in any one of three selected switching orientations. The device disclosed in the '022 Patent has proven itself to be generally satisfactory in commercial utilization, however, the apparatus of the '022 Patent requires the reaction forces caused by switching operations to be resisted by the double-acting cylinder mechanism thereof. This fact leads to increased maintenance requirements because the precise alignment of the switching apparatus under the action of the double-acting cylinder is necessary in order that switching operations can be properly carried out.
The present invention comprises an improved switching apparatus useful in conjunction with horizontal switches and in similar operations which overcomes the foregoing and other problems long since associated with the prior art. In accordance with the broader aspects of the invention, a switching apparatus includes switching members which are positioned against fixed stops during switching operations. Because the fixed stops precisely position the switching members, the frequency of maintenance operations which are necessary in order to maintain proper alignment of the switching apparatus of the prior art device is substantially reduced.
More specifically, the switching apparatus of the present invention utilizes a pair of opposed rotary solenoids. The rotary solenoids are each positively driven in both directions, and an interlock has provided for eliminating the possibility of simultaneous actuation of the two rotary solenoids. Upon actuation of one of the rotary solenoids to position the switching member controlled thereby, the actuated switching member is moved into engagement with the switching member of the opposite rotary solenoid which in turn abuts a fixed stop. In this manner, precise alignment of the switching members is constantly maintained.